For many years humidity control devices have used Nylon strips or ribbons as a moisture responsive element such as shown in the Keith M. Nodolf U.S. Pat. No. 3,949,607, issued April 13, 1976, and the Maynard L. Thompson U.S. Pat. No. 3,288,961, issued November 29, 1966. While the normal calibration of such humidity controls or humidity responsive devices has been accomplished by a screw connecting a pivoted lever supporting the element to an adjusting member or cam, such calibration adjustment is not sufficient to compensate for changes in the rate of expansion of such Nylon strip elements. The present invention is concerned with an additional adjustment which can be made prior to the normal calibration of the humidity responsive device to adjust for the variations in rate of expansion of such elements.
Specifically, the adjustment characteristics of the humidity responsive device is changed by an additional lever engaging the humidity set point adjusting cam to provide for variations in the output of the adjustment to compensate for different characteristics of the Nylon element. A variation of an L.sub.1 /L.sub.2 ratio makes possible (1) the adaptation of the same cam to sensing elements of different activities, and (2) the adaptation of the same cam and sensing element to variations in scales.